As flight vehicle capabilities are expanded to more complex missions and dynamic environments, the ability to actively sense undesirable aerodynamic forces acting on the vehicle and generate feedback strategies to mitigate these disturbances greatly improves robustness. That is, unmanned aerial vehicles (UAVs), small-unmanned aerial systems (sUAS), and other small aircraft, particularly those intended for use in urban or otherwise cluttered environments, face extreme constraints with regard to stability of the aircraft's state (e.g., attitude and position) when faced with atmospheric turbulence and gusts.
In particular, high winds, cluttered urban environments, and proximity to other vehicles can introduce disturbances that are often difficult to reject with existing flight control technologies. Indeed, when navigating urban canyons, a one to two meter offset in course could lead to obstacle collision, mission failure, or vehicle loss. Gust rejection and vehicle stability is particularly crucial for generating clear and comprehensible surveillance video, a primary duty of these small aircraft. Assymetric gusts, flutter, and near-stall flight are all examples of disturbances that could be effectively rejected with on-wing sensing that estimates airflow characteristics and aeroelastic effects on the airframe. For example, UAVs are often subjected to asymmetric gusts caused by the channeling and occlusions of flow in urban canyons—flow fields unique to this environment.
While traditional inertial navigation systems (INS) are effective for vehicle stabilization, they incur an inherent lag in attitude correction, as errors must be measured before they are corrected. Further, while effective, some previously investigated proprioceptive sensing methods that use strain and pressure-based measurements require relatively complicated structural and aerodynamic modeling. For example, commonly owned U.S. Patent Publication No. 2016/0200420 to McKenna et al. titled System and Method for Unwanted Force Rejection and Vehicle Stability discloses techniques for providing gust rejection and increasing vehicle stability via proprioceptive sensing techniques using strain gauge embedded within the wings.
As flight vehicle capabilities are expanded to more complex missions and dynamic environments, new sensor regimes may be employed to improve robustness, survivability, and mission effectiveness. For example, the ability to sense dynamically disturbance forces and moments acting on the vehicle and the ability to use these sensed quantities in feedback strategies to mitigate disturbances. In fact, these capabilities may be combined with many discretized flaps on the vehicle wing to enable localized, high-resolution disturbance sensing and rejection. Consequently, small aircraft, such as UAVs and sUAS, would greatly benefit from gust rejection through increased maneuverability, expanded flight envelopes, and improved performance.
Accordingly, a need exists for a system and method to quickly detect and counter changes in lift, onset of stall, and flutter, which, as disclosed herein, may be achieved using a distributed pressure sensor system.